Solid emulsion blasting agents comprising nitric acid, inorganic nitrates, and fuels



United States Patent SOLID EMULSION BLASTING AGENTS COMPRIS- ING NSITRIC ACID, INORGANIC NITRATES, AND FUEL Neil E. Gehrig, Schuylkill Haven, Pa., assignor to Atlas Chemical Industries, Inc, Wilmington, Del., a corporation of Delaware No Drawing. Original application May 13, 1963, Ser. No. 280,128, now Patent No. 3,164,503, dated Jan. 5, 1965. Divided and this application Dec. 23, 1963, Ser. No. 340,578

18 Claims. (Cl. 149-18) This application is a divisional application of copending application Serial No. 280,128, filed May 13, 1963, now US. Patent 3,164,503.

The present invention relates to blasting agents containing nitric acid as an essential component thereof and particularly to blasting agents which are comprised of an aqueous solution of nitric acid, and an insensitive, immiscible fuel.

The compositions of the present invention have the advantage of performing as powerful explosives but do not contain a sensitive high explosive component. The present compositions are highly insensitive to mechanical shock but are sensitive to detonation when initiated by the booster or priming means commonly used to initiate ammonium nitrate blasting agents.

The compositions of the present invention are dispersions and comprise an aqueous solution of nitric acid and an insenstive, immiscible fuel. The fuel component is immiscible with the nitric acid solution and is substantially unreactive with the nitric acid component under normal conditions of mixing and storage. The compositions of the present invention are relatively stable dispersions, that is, there is little separation of the components into individual phases, for at least 8 hours and generally the compositions are stable for periods of several months. The compositions of the present invention contain nitric acid and, on the basis of 100 parts by weight of an aqueous solution of nitric acid containing between about 30% and about 80% by weight of nitric acid, generally contain from about 3 to about 500 parts by weight of an insensitive, carbonaceous fuel immiscible in the nitric acid solution. Some embodiments of the invention may also include ammonium or an alkali metal nitrate, for example, the granular mixture and solid dispersion forms of the present invention described anon.

The term immiscible as used herein is defined as an inability to form a stable, homogeneous mixture with an aqueous solution of nitric acid containing between about 30% and about 80% by weight of nitric acid.

The various suitable components, their proportions, and the physical forms of the present invention will be described in more detail in the following sections:

NITRIC ACID The nitric acid component of the present mixtures preferably is an aqueous solution of nitric acid containing between about 30% and about 80% by Weight of nitric acid. Aqueous solutions of about 60% by weight of nitric acid aptly suited to use in the present mixture are readily available in the commercial market. Such solutions are less reactive and much less expensive than more highly concentrated nitric acid solutions. Although a more 3,242,019 Patented Mar. 22, 1966 Total weight HNO, in the mixture Total weight of HNO in the miXture+ Total weight of water in the mixture Nitric acid having a concentration of less than about 30% frequently yields a product which is insensitive to normal detonation means. Nntric acid having a concentration of greater than about 40% is usually preferred and generally produces a final composition having a satisfactory detonation velocity and sensitivity.

INSENSITIVE CARBONACEOUS FUEL MATERIAL The term insensitive as used herein is defined as insensitive to detonation by a No. 8 blasting cap. A No. 8 blasting cap has the explosive equivalent of 2.00 grams of mercury fulminate.

The compo-sitons of the present invention include a fuel material which is immiscible with an aqueous solution of nitric acid. That is, the two components may be utilized to produce a dispersion. Generally hydrocarbons Whether paraffinic, olefinic, naphthenic, aromatic, saturated or unsaturated are suitable as the insensitive, carbonaceous fuel component. Carbohydrate materials, for example, sugars in dry form, such as sucrose, or in solution, such as molasses, may be utilized as supplemental fuels. Examples of insensitive, immiscible, carbonaceous fuel materials suited to use in the present mixtures are diesel fuel oil, or similar petroleum products, paraflinic waxes, vegetable oils, and powdered carbon. Generally the fuel material selected for use in the present invention will depend upon the desired physical form of the final product, i.e., if a pourable liquid product is desired, a liquid or semi-liquid fuel would be utilized; if a solid product is desired, a predominantly solid fuel would be utilized. Liquid fuels which are particularly suited to use in the slurry mixtures of the present invention are refined mineral oils which are liquids at normal temperatures and have a flash point above 100 F. In the granular mixtures contemplated by the present invention, No. 2 fuel oil is eminently suited to use. The specification for No. 2 fuel oil are well-known and are set forth in the US. Department of Commerce Commercial Standard CS 12-48. No. 2 fuel oil has a flash point above 100 F., a distillation point of 675 F. and a maximum Saybolt Universal viscosity at F. of seconds. Petroleum cuts sometimes referred to as low or partially refined oils are also suitable fuel components. Generally the fuels of the present compositions are unreactive with nitric acid under normal conditions of mixing and storage, that is, little, if any, fumes of the oxides of nitrogen will noticeably be given off by the mixture. =Paraffins or paraffinic-based waxes are eminently suited to use as an unctuous fuel component.

3 AMMONIUM AND METAL NITRATE While commercially available fertilizer grade ammonium nitrate is suited to use in the mixture of the present invention sodium and potassium nitrates may also be used. Preferably, the nitrate component is in particulate form, that is, having a size that will pass a No. 8 US. Standard screen. A nitrate component in particulate form, for example, in the form of prills, pellets or granules, is aptly suited to use in the present mixtures.

OTHER ADDITIVES The compositions of the present invention may include other ingredients to modify the physical properties of the mixture. For example, a particulate ammonium nitrate suited to use as a starting material in the granular form of the present compositions may, if desired, initially be treated with a thin coating of protective material to minimize attrition and caking of the particles. For example, a thin coat of clay, diatomaceous earth, or organic agents, such as a mixture of sulfonates of monoand/or dimethyl naphthalenes, are frequently used as additives to particulate ammonium nitrate. Generally the inorganic additives such as clay are present in an amount of from about 0.5 to about 5.0% by weight of the ammonium nitrate. The organic additives are frequently effective in amounts as low as 0.05% by weight of the ammonium nitrate.

The present mixtures may include small amounts of a suitable surfactant, generally between about 3 and about 50 parts by weight based on 100 parts of an aqueous solution of nitric acid containing between about 30% and about 80% by weight of nitric acid to aid in obtaining and maintaining a homogeneous mixture. Generally from about 3 to about 30 parts by weight based on 100 parts of the nitric acid solution of a surfactant is sufiicient to emulsify the present mixtures, however, additional surfactant, up to about 50 parts may be added without noticeable harmful effects. The surplus surfactant may be beneficial in that it supplies an additional supplemental fuel to the mixture.

The present mixtures may also include small amounts of a stabilizing material, generally between about 1 and about 20 parts by weight based on 100 parts by weight of nitric acid solution, to prevent the water phase of the mixtures from separating from the fuel component. If either the surfactant or the stabilizer materials are insensitive, carbonaceous and immiscible in aqueous nitric acid solutions, they may aid in fulfilling the fuel requirement described in the above section relating to fuels.

The sensitivity and detonation velocity of the slurry and solidified dispersion forms of the present invention usually may be stabilized by the addition of an inert, nonexplosive propagation sustaining material, for example, expanded particulate perlite, or hollow glass balls. Generally about 1 part by weight of the propagation sustaining material, based on 100 parts by weight of a 60% nitric acid solution, is required to obtain an advantage and usually more than about 70 parts fails to yield further improvement. Expanded perlite, a commercially available material, is the mineral perlite, a volcanic glass composed largely of aluminum silicate, which has been put through a heating process so that it is expanded into an extremely light cellular form.

The various forms of the present invention and preferred ranges of the components in each form are discussed below:

PHYSICAL FORMS OF MIXTURES The compositions of the present invention may be compounded in various physical forms, for example, 1) a granular form, that is, where a dispersion of an aqueous solution of nitric acid and an immiscible fuel is utilized to coat discrete granules of ammonium nitrate; (2) a slurry form wherein a dispersion of an aqueous solution of nitric acid and an immiscible fuel are slurried together. In a preferred embodiment the slury form also includes ammonium nitrate, and (3) a solidified form wherein an aqueous solution of nitric acid, an immiscible fuel and ammonium nitrate are emulsified and solidified. The latter solid emulsion form is adapted to be further modified to produce mixtures which may be molded or cast and in a short period of time will harden to a solid mixture without further curing or treatment.

GRANULAR MIXTURES The granular mixtures of the present invention utilize a particulate ammonium nitrate component. This component may be coated or uncoated. Preferably the ammonium nitrate is of a size that will substantially entirely pass a No. 6 mesh US. Standard screen. Since the present granular mixtures utilize a high proportion of ammonium nitrate, the proportions of the granular mixtures will be defined as being based on 100 parts by weight of the ammonium nitrate component. Using this basis, the granular mixtures preferably contain from about 3 to about 13 parts by weight of an aqueous solution of nitric acid containing from about 30% to about by weight of nitric acid and a total of from about 4 to about 13 parts by weight of insensitive, immiscible, fuel material.

The granular mixtures of the present invention may be easily compounded by starting with the proper proportions of ammonium nitrate, nitric acid and fuel material and vigorously mixing the components.

Table I shows the results of a series of comparative tests of the prior art ammonium-nitrate diesel fuel oil mixtures and the blasting mixtures of the present invention. In each test the ammonium nitrate was weighed and a weighed amount of additive or additives vigorously mixed therewith. In each test No. 2 diesel fuel oil was utilized as the insensitive, immiscible, carbonaceous fuel material. Mixes 2, 3, 5, 6, 8 and 9 are illustrative of the present invention. The nitric acid component utilized in these mixes was an aqueous solution of nitric acid containing 60% by weight of nitric acid. In compounding the illustrative mixes of the present invention, a slight cooling was noted when the components and the aqueous solution of nitric acid were mixed. When the nitric acid component was added the color of the mixture changed from an off-white to a light green to a canary yellow. The illustrative mixes were allowed to stand for two hours to cure. The density of the ammonium nitrate starting material was calculated to be in the range of between about 0.8 and 0.9. After curing the density of the mixtures of the present invention were calculated to be in the range of between about 1.1 and about 1.3. In each case the mixes were packed in a portion of ceramic pipe 3" in inside diameter and 10 in length. The packed mixture was primed with a M pound charge of Composition B (40% trinitrotoluene and 60% cyclotrimethylenetrinitramine). The charge of Composition B was detonated by means of an electric blasting cap and the detonation velocity of the explosive mixtures was determined by the Dautriche method wherein the velocity of the mixture being tested is compared to the known velocity of a length of detonating cord. The ammonium nitrate pellets used in mixes 1, 2 and 3 were of a size that would substantially entirely pass a No. 8 mesh US. Standard screen and would substantially entirely be held on a No. 35 mesh US. Standard screen. The pellets were coated with about 3% by weight of finely divided clay. The ammonium nitrate prills used in mixes 4, 5 and 6 were of a size that would substantially entirely pass through a No. 8 US. Standard screen and be held on a No. 35 US. Standard screen. The prills, mixes 4, 5 and 6 were treated with about 0.05% by weight of an organic parting agent consisting of a mixture of sulfonates of monoand/or dimethyl naphthalenes. The ammonium nitrate granules used in mixes 7, 8 and 9 were sized to substantially en- 3,242,019 6 tirely pass through a No. 6 U.S. Standard screen and be ample, 7.6 parts by weight of a low refined oil (Atreco F held on a No. 35 U.S. Standard screen. The granular oil), 3.8 parts by weight of finely divided diatomaceous amonium nitrate was coated with about 3% by weight of earth and 5.9 parts by weight of an aqueous solution of Table II Ammonium Diatomace- 60% nitric Cartridge Detonation Mix No. nitrate Oil ous earth acid size Primer velocity (IL/second) 100 7. 7 3. 7 3' x 750 grams gelatin Failed dynamite. 100 7. 7 3. 7 6' x 10 do Failed 100 7. 6 3.8 5. 9 3" x 10' %]pouud Comp. 7, 635 100 7. 6 3. 8 5. 9 3' x 10' 750 grams gelatin 7, 681

dynamite. 100 7. 6 3. 8 5. 9 4" x 10 -d0 7, 717

finely divided clay. All values in the following table are nitric acid (60% by weight nitric acid), were mixed with parts by weight. 100 parts by weight of particulate ammonium nitrate. Table I The mixture was then placed in a 3" x 10" portion of PELLETS ceramic pipe (3" in diameter and 10 in length) and primed with 750 gram charge of gelatin dynamite. The

Mix No. Ammonium #2 diesel fuel Nitric acid Velocity detonation velocity of the mix! as determinfid by the nitrate il (feet/Second) Dautriche method was 7636 feet per second. The other mixes shown on Table II were similarly compounded igg g- 228 and tested except that mixes 10 and 11 contained no 100 1 1 nitric acid component.

Table III shows the results of a series of tests of the PRILLS blasting agent mixtures of the present invention containing carbohydrate material as a supplementary fuel material. 100 e1 ,305 In each mix, the particulate ammonium nitrate compoigg 2-3 3 3 nent was coated with about 0.05% by weight of the organic parting agent used in Mixes 4, 5 and 6 of Table I GRANULES and was of a size which would substantially entirely pass a No. 8 U.S. Standard screen and substantially entirely be 100 6 1 Failed :held on a No. 35 U.S. Standard screen. The nitric acid 100 6 .2 1- 3.2 5, 577 component in each mix was an aqueous solution of nitnic 5:577 acid containing 60% by weight of nitric acid. For example, in Mix 15, 5.0 parts by weight of No. 2 diesel fuel oil, Table II shows the results of comparative tests between 40 33 parts b i ht of granulated Sugar, d 8,7 parts typical prior art nitrocarbonitrate blasting agents and by weight of an aqueous solution of nitric acid (containgranular blasting agent mixtures of the present inveni 60% by i h f i i id) were added and b tion. Mixes 10 and 11 are typical prior art nitrocarbohl i d i h 100 parts b i ht f ammonium ni r ng agents Mixes 13 and 14 are illusnitrate. The mixture Was then packed into a 3" x 10" trative of the mixtures of the present invention. The ceramic pipe and primed witha' /2 pound charge of Comammonium nitrate material in each of the mixes was sized position B, Th det ti n velocity d te i d b th so that would pass through a No. 35 U.S. Standard Dautriche method was 9992 feet per second. The other screen and substantially 100% would be held on a No. mixes shown on Table III were compounded and tested 100 U.S. Standard screen. In each mix shown on Table in a similar manner. The particulate carbon and glucose II, the oil component was a partially refined oil, Atreco F 50 mixture of Mix 17 was a waste product of a sugar reoil, a product of Atlantic Refining Company. The nitric finery and consisted of spent activated carbon saturated acid component used in mixes 12, 13 and 14 was an aquewith glucose.

Table III Parts by weight Form of am- Mix No. monium Mixture of Detonation nitrate Ammonium #2 diesel fuel Granulated Molasses particulate nitric velocity nitrate oil sugar eagbgggend acid (feet/second) 100 5. 8.7 9992 100 5. 12. 5 9703 Pellets- 100 5. 12. 5 9055 ous solution containing 60% by weight of nitric acid. The SLURRY MIXTURES various additives in each mix were separately added and incorporated into the ammonium nitrate material by vigorous stirring. The mixes were each packed into a portion of ceramic pipe and primed with a high velocity booster, for example, mixes 10, 11, 13 and 14 were The present invention also provides blasting agents in the form of dispersions which may be compounded in slurry form. The blasting slurries contemplated by the present invention are pourable and liquid or semi-liquid Primed with a 750 gram charge of gelatin dynamite and in nature. Since the mixtures of the present invention in i 2 was primed with a 1 pound charge of c slurry form contaln an aqueous solution of nitric acid i ]3 h booster was fi d b means f a blasting and may be compounded w thout ammonium IlltlatQdllG cap. The detonation velocity of the mixes was deterproportions of the slurry mixture are based on the nitric mined by the Dautriche method. In mix 13, for exacid component. Based on parts by weight of an aqueous solution of nitric acid containing between about 30 and about 80% by weight of nitric acid, the slurry mixtures include from about 3 to about 65 parts by weight of an insensitive, immiscible, carbonaceous fuel independent of the amounts of surfactant and stabilizer. The slurry mixtures of the present invention may, in addition to nitric acid and fuel, contain an ammonium, potassium or sodium nitrate component. In such case, based on 100 parts by weight of an aqueous solution of nitric acid containing between about 30 and about 80% nitric acid, up to about 550 parts by weight of the nitrate component may be included. An advantage of the slurry mixtures of the present invention which contain nitric acid and either ammonium or potassium nitrate is that under normal conditions such mixtures exhibit neither the amount of normally titratable acidity nor the amount of corrosiveness that would be expected from the amount of nitric acid included in the mixture. The fuel component is immiscible in water and preferably is an unctuous material such as paraflin or refined mineral oil. Of the unctuous materials which are suited to use, materials which are liquid at ambient temperature are particularly useful. A suitable fuel fulfilling the requirements of the present invention is a refined hydrocarbon oil from which substantially all unsaturated hydrocarbons have been removed. Mixtures which contain relatively small amounts of nitric acid, as compared to the amount of the nitrate component, for example, those containing at least about 300 parts by weight of the nitrate component as compared to 100 parts by weight of nitric acid solution, are generally found to be thick, almost paste-like mixtures while mixtures containing a greater amount of nitric acid tend to be fluid and generally are quite flowable mixtures. The thick, almost paste-like mixtures frequently are suitable starting materials for producing the solid mixtures of the present invention which are described below. Because the slurry mixtures are fluid the particulate nitrate starting material need not be coated with clay or other parting agent. The aqueous nitric acid solution of the present invention exhibits a preferred sensitivity when they contain at least about 40% by weight of nitric acid.

The slurry mixtures of the present invention are in the physical form of stable dispersions. The present dispersions evidence no separation of components when stored at temperatures in the range of 75 to 85 F. for periods of at least 8 hours. Frequently the present dispersions are stable for periods of 6 months or more.

An acid-resistant stabilizer in an amount between about 1 and about 10 parts based on the Weight of the nitric acid solution component as 100, may be added to the slurry mixture to prevent separation of the components. Generally no stabilizer is required if the slurry is mixed and used in the same 24 hour period; however, where the slurry is to be stored a stabilizer is desirable. A high molecular weight copolymer of methyl vinyl ether-maleic anhydride is a useful stabilizer. The product sold under the trade name Grantez AN169 by General Aniline & Film Co. is a copolymer of methyl vinyl ether-maleic anhydride having a mol weight of about 1,250,000 and is suited to use. A low density colloidal silica is a useful stabilizer. The product Cab-O-Sil M5 manufactured by the Cabot Corporation is suited. Synthetic polymers and copolymers, particularly those of acrylamide, have been found suited to use as stabilizers. A mixture of such polymers and copolymers, sold under the trade name Cyanogum 41, a product of American Cyanamid Co., is a suitable stabilizer. Other useful stabilizers, for example, are polyacrylic acid, and other water soluble acrylic polymers.

The present slurry mixtures may contain between about 3 and about 50 parts, based on the weight of the nitric acid solution as 100, of an acid resistant surfactant capable of forming an emulsion of oil in water. Generally a minimum of about 3 parts is required to form a satisfactory oil emulsion between the unctuous fuel component and the aqueous solution of nitric acid. Any excess, to about 50% based on the weight of nitric acid, yields no noticeable ill effects and may be a supplemental source of insensitive carbonaceous fuel. Sorbitan monopalmitate, sorbitan monooleate and sorbitan monostearate have been found to be acid resistant and suited to use in the emulsion slurries of the present invention.

The present slurry mixtures may contain an inert, nonexplosive propagation sustaining material in an amount suflicient to stabilize the sensitivity and detonation velocity during storage of the slurries. Suitable propagation sustaining materials are, for example, perlite and hollow glass balls. Preferably the propagation sustaining materials are of a size that will pass a No. 8 mesh U.S. Standard screen. Generally a minimum of about 1 part of the propagation sustaining material, based on 100 parts by Weight of an aqueous solution of nitric acid containing between about 30 and about by weight nitric acid, is required to give noticeable results. Usually an excess of over about 70 parts by weight of the propagation sustaining material on the foregoing basis of nitric acid yields no obvious additional advantages.

The mixtures of the present invention in slurry form may be compounded by mixing the proper proportions of an aqueous solution of nitric acid and insensitive, immiscible fuel material together. If an additional component such as a stabilizer or a surfactant is utilized, the additional component is preferably blended with and added along with the fuel material.

Blasting agent emulsions in slurry form are contemplated by the present invention. Preferably such emulsions are compounded by initially blending an acidresistant surfactant with an insensitive immiscible fuel component. Preferably the fuel is a refined or partially refined oil, paraflin or paraffin-based wax. If sorbitan monooleate is used as the emulsifying component, it is desirable to mix the sorbitan monooleate with a small amount of water to facilitate solution of the sorbitan monoleate in the mixture. If a stabilizing component is to be utilized in addition to the surfactant, it may be added along with the fuel-surfactant blend. The fueladditive blend is then thoroughly mixed with the ammonium nitrate component. The nitric acid component is added and slowly stirred into the mixture and the final product heated (to a temperature within the range of from about 80 F. to about 150 F.) to remove a portion of entrapped air. The latter heating step increases the density of the final mixture and produces a more stable emulsion.

Table IV shows the results of a series of tests of slurry mixtures of the present invention. In Mix No. 18, 7.8 parts by weight of sorbitan monooleate and 7.8 parts by weight of water were initially blended to facilitate the latter solution of the sorbitan monoleate in the final slurry mixture, 20 parts by Weight of a refined mineral oil marketed under the name Nujol by Plough, Inc., was mixed with the surfactant-water blend. This mixture was then added to and incorporated in 264 parts by weight of particulate ammonium nitrate. In order to speed solution the ammonium nitrate component was sized so that substantially passed through a No. 35 U.S. Standard screen. 100 parts by Weight of an aqueous solution of nitric acid (containing 60% by weight of nitric acid) was slowly stirred into the mixture. The mixture was stirred until an emulsion formed, at which time the mixture was noticeably thickened. The emulsified product was then heated by means of a steam bath to F. While still fluid, the mixture was removed from the heat. A sample of the mixture was tested for emulsion stability by storing the sample at a temperature of from 75 to 85 F. and noting any evidence of component separation over a period of time. The mixture of Mix No. 18 Was found to have a minimum stability time of 8 hours. While a minimum stability time is given for each of the mixes, it will be understood that the present emulsions may be stable for much longer periods of time. The dispersions of the present invention have a minimum stability time of at least 8 hours. The mixture was tested by packing a portion of the mixture into a ceramic pipe 3" in diameter 10 to about 80 parts by weight of a fuel component, and at least 6 parts by weight of an acid resistant surfactant, such as sorbitan mouosterate, sorbitan monopalmitate or sorbitan monooleate, as the emulsifying agent. Usually and 1 long, primed with a pound charge of Comover 50 parts of surfactant, based on 100 parts of the position B. The detonation velocity determined by the nitric acid component, yields no obvious benefit. The Dautriche method was 8834 feet per second. The resolidified mixtures of the present invention may also maining mixes shovvn on Table IV were compounded and include a stabilizer component. Suitable stabilizer comtested in the same manner. The surfactant in Mixes 20 ponents are described in the foregoing section describing through 23 was sorbitan monostereate and in Mixes 24 Slurry Mixtures. If a stabilizer component is used, it through 33 was sorbitan monopalmitate. In Mixes 22 usually produces no increase in effectiveness above about and 23, a stabilizer of Cyanogum 41, a high molecular 20 parts by weight based on 100 parts of the nitric acid weight mixture of acrylamide and N,N'-methylene bissolution component. If any additives are utilized which acrylamide monomers, was utilized. In Mixes 24 through meet the requirements for a fuel component, that is they 33, a stabilizer of Gantrez AN-169, a high molecular are carbonaceous, immiscible and insensitive to detonaweight copolymer of methyl vinyl ether-maleic anhydride. tion, their weight may be considered as additional fulel. Mix 29 utilized a stabilizer of Cab-O-Sil M-S, a high Generally the mixtures of the present invention form a grade colloidal silica. The stabilizer was added to the melt in a range between 100 F. and 135 F. and this fuel component prior to mixing the fuel and ammonium temperature is sufiicient to form the present solid mixnitrate components. In Mix 29 paraffin was utilized as tures. For safety purposes, it is preferred that the comthe fuel and colloidal silica as a stabilizer. In Mixes 34 pon n s be chosen so that the mixture has a melting point through 36 an inert, non-explosive propagation sustaining not substantially higher than about 150 F. material of particulate expanded perlite was added to The pr s nt solid disp rsions may Contain an inert, non- .stabilize the detonation velocity and detonation sensiexplosive propagation sustaining material in an amount tivity during storage. sufficient to stabilize the sensitivity to detonation and Table IV Parts by weight Detona- Propagation Minimum Mix Insensitive Nltr 1eac1d tion Density velocity stability No. Ammonimmiscible Sorbitan Sorbitan Sorbitan (bas1s:60% Emulsion sustaining (feet/ time ium fuel monomonomono- HNO Water stabilizer material second) nitrate material oleate stearate palmitate aqueous solution) 264 100 1.5 8, s34 8h0ul'S. 264 100 1.5 13, 755 D0. 645 100 1.5 16,000 Do. 128 100 1.6 20, 350 Do. 261 100 2.1 1.6 16,500 5wssks 345 100 5. 2 1. 5 16, 000 o. 530 6.4 100 6. 4 1.4 10, 300 timonths. 505 26. 26.7 100 6.6 1.3 14, 300 Do. 123 5. 5.0 100 7.5 1.4 ,200 D0. 102 20. 20.0 100 7.5 1.2 17,900 Do. 62.5 40.0 40.0 100 7.5 1.0 14,000 Do. 358 54.9 100 5.0 10, 650 D0. 114 20.0 10.0 100 6.3 1.2 19,611 Do. 70 16.0 8.0 100 6.0 1.2 21,200 Do. 20 11.4 5.7 100 5.7 1.2 15,500 Do. 0 9,5 4.8 100 4.8 1.2 15,000 Do. 450 40.0 13.4 100 3.3 1.2 14,000 Do. 167 23.4 10.0 100 6.7 1.2 16,000 Do. 66 16.0 8.0 100 6.0 1.2 18,000 Do.

1 Mixes 20 and 23 were thick, paste-like mixtures.

detonation velocity during storage of the dispersions. S OLI!D LFIED MIXTURES Suitable propagation sustaining materials are generally of The present Invention also contemplates ol mtroa size which will pass a No. 8 mesh U.S. Standard screen. r nil' miXlllreS Whioh y be Q Cast Materials suitable for this purpose are, forexarnple, perlite extruded into any desired shape. The SOlId rmxtures of and hollow glass balls. Generally a minimum of about the present invention are related to the slurry emulsions 1 part of th propagation t i i i l, b d on described above, however, instead of remalmng 1n slurry 100 parts by Weight of an aqueous solution of nitric acid form the mixtures solidify. The solid mixtures of the containing between about 30 and about 80% by weight present invention require that (1) the components be of nitric acid, is required to give noticeable results. Usuproportioned within rather specific ranges, (2) the final ally an excess of over about 70 parts by Weight of the mixture be heated to form a melt and drive off excess propagation sustaining material on the foregoing basis entrapped air. The proportions of components which of nitric acid yields no obvious additional advantages. are suited to form solid mixtures overlap the range of Table V shows the composition of a series of solidified components suited to provide a slurry form of the explodispersions and the results of performance tests carried sive. 'Ilhe slurry formulas in the overlap area are thick, out utilizing the solid mixtures. For example, Mix 37 almost paste-like mixtures and may be transformed into 5 was compounded by initially blending 35.9 parts by weight solid mixtures by extending the heatmg step. The solidiof refined mineral oil and 26.8 parts by weight of sorbitan fied mixtures include ammonium potassium or sodium monostearate, mixing the blend with 505 parts by weight nitrate as a component. On the basis of 100 parts by of particulate ammonium nitrate of a size that will subweight of an aqueous solut1on of nitric acid containing stantially entirely pass a No. 35 U.S. Standard screen, and from about 30% to about i0% by weight of nitric acid, adding parts by weight of an aqueous solution of nitric the solid fied rmxtures contam at least 30 0 parts by weight acid containing 60% by weight of nitric acid. The resultot the nitrate component. Generally satisfactory solidiing mixture was stirred until the mixture stittened and then fied mixtures based on 100 par-ts by Weight of the nitric heated from about 100 to about F. to rid the mixacid solution component contain between about 300 and ture of excess air bubbles introduced in the mixing operabout 550 parts of the nitrate component, from about 20 75 ation. The heated mixture was poured into a portion of ceramic pipe 3 in diameter and in length. The mixture solidified in about two hours. The solid mixture was then primed with a pound charge of Composition B and the Composition B initiated by a blasting cap. The detonation velocity determined by the Dautriche method was determined to be 12,200 feet per second. A sample of the mixture was stored at temperatures ranging between 75 and 85 F. and after a period of 6 months was found. to evidence no component separation. The other mixes shown in Table V below were carried out in the same manner. In Mix 39, 46.5 parts by weight of a paraffinicbased wax (90% paraffin and 10% ethyl vinyl acetate) was utilized as the fuel component. Mixes 41 and 42 are examples of solidified mixtures which contain perlite as an inert, non-explosive propagation sustaining material to stabilize the detonation velocity and detonation sensitivity during storage.

In general, the density of the mixtures is determined by the amount of air entrapped in the mixture. A product having a density of well over 1 may be produced by removing a substantial amount of the entrapped air. Entrapped air may be removed by placing the mixture immediately after stirring, and before it has solidified, in an open vessel and heating. In order to insure that the solid mixture will have a satisfactory sensitivity to detonation, it is desirable that a small amount of air remain in the mixture. A product having a density of from about 1.0 to about 1.4 and having a satisfactory sensitivity to detonation may be produced by heating the mixture after stirring to a temperature sufiiciently high to form a melt. Generally such temperature is in the neighborhood of about 100 F. It is desirable for safety purposes, that the components be chosen so that the melting step can be carried out at a temperature not 12 group consisting of ammonium nitrate and alkali metal nitrates, from about 20 to about 80 parts by weight of an insensitive immiscible fuel material and from about 6 to about 50 parts by weight of an acid-resistant surfactant.

4. A composition of claim 3 wherein the insensitive, immiscible fuel material is selected from the group consisting of diesel fuel, mineral oil, parafiin, paralfin-based waxes, vegetable oils, and powdered carbon.

5. A composition of claim 4 wherein the surfactant is selected from the group consisting of sorbitan monooleate, sorbitan monopalmitate and sorbitan monosterate.

6. A blasting composition in the form of a solid emulsion consisting essentially of 100 parts by weight of an aqueous solution of nitric acid containing from about to about 80% by weight of nitric acid, from about 300 to about 550 parts by weight of nitrate selected from the group consisting of ammonium nitrate and alkali metal nitrates, from about 20 to about 80 parts by weight of an insensitive immiscible fuel material and from about 6 to about 50 parts by weight of an acid-resistant surfactant, and a maximum of about 20 parts of an acid-resistant stabilizer.

7. A composition of claim 6 wherein the acid-resistant, stabilizer is selected from the group consisting of colloidal silica, polymers and copolymers of acrylamide, a copolymer of methyl vinyl ether-maleic anhydride, polyacrylic acid and water-soluble acrylic polymers.

8. A composition of claim 6 wherein the surfactant is selected from the group consisting of sorbitan monooleate, sorbitan monopalmitate and sorbitan monostearate.

9. A composition of claim 6 wherein the insensitive, immiscible fuel material is selected from the group consisting of diesel fuel, mineral oil, paraffin, paraffin-based significantly in excess of 150 F. waxes, vegetable oils and powdered carbon.

Table V Parts by weight Detonation Mix No. Insonsitive, Gantrez Density velocity Ammonium carbonaceous Sorbitan AN-169 Perlite Nitric acid nitrate immiscible monostcarate stabilizer fuel The term consisting essentially of as used in the claims, includes compositions containing the named components and other ingredients which do not deleteriously affect the compositions for the purposes stated in the specification.

What is claimed is:

1. A blasting composition in the form of a solid emulsion consisting essentially of 100 parts by weight of an aqueous solution of nitric acid containing from about 30% to about 80% by weight of nitric acid,

from about 300 to about 550 parts by weight of ammonium nitrate,

from about 20 to about 80 parts by weight of an insentive, immiscible fuel material, and

from about 6 to about parts by weight of an acidresistant surfactant.

2. The blasting composition of claim 1 wherein the insensitive, immiscible fuel material is selected from the group consisting of mineral oil, paraffin, and parafiin-based waxes.

3. A blasting composition in the form of a solid emulsion consisting essentially of 100 part by weight of an aqueous solution of nitric acid containing from about 30% to about 80% by weight of nitric acid, from about 300 to about 550 parts by weight of nitrate selected from the 10. A composition of claim 6 wherein the insensitive, immiscible fuel is paraffin.

11. A composition of claim 6 wherein the insensitive, immiscible fuel is a paraffin-based wax.

12. A method of preparing a blasting composition comprising the steps of blending from about 20 parts to about parts by weight of insensitive, immiscible carbonaceous fuel with from about 6 parts to about 50 parts by weight of a acid-resistant surfactant, mixing from about 300 parts to about 550 parts by weight of nitrate selected from the group consisting of ammonium nitrate and alkali metal nitrates with said blend of carbonaceous fuel and acid-resistant surfactant, adding parts by weight of an aqueous solution of nitric acid containing from about 30% to about 80% by weight of nitric acid to said blend of fuel, surfactant and nitrate, agitating said mixture to form an emulsion, heating said emulsion to a temperature less than about F. to form a melt and allowing said emulsion to cool and solidify.

13. A method of preparing a blasting composition comprising the steps of blending from about 20 parts to about 80 parts by weight of insensitive immiscible carbonaceous fuel with from about 6 parts to about 50 parts by weight of an acid-resistant surfactant and a maximum of about 20 parts by weight of an acid-resistant stabilizer, mixing from about 300 parts to about 550 parts by Weight of nitrate selected from the group consisting of ammonium nitrate and alkali metal nitrates with said blend of carbonaceous fuel, acid-resistant surfactant and acid-resistant stabilizer, adding 100 parts by weight of an aqueous solution of nitric acid containing from about 30% to about 80% by weight of nitric acid to said blend of fuel, surfactant, stabilizer and nitrate, agitating said mixture to form an emulsion, heating said emulsion to a temperature less than about 150 F. to form a melt and allowing said mulsion to cool and solidify.

14. The method of claim 13 wherein the melted emulsified mixture is agitated in an open vessel to remove sufficient entrapped air to produce a product having a density between about 1.0 and about 1.04.

15. The method of claim 12 wherein the melted emulsified mixture is agitated in an open vessel to remove sufiicient entrapped air to produce a product having a density between about 1.0 and about 1.4.

16. A method of preparing a blasting composition comprising the steps of blending from about parts to about 80 parts by weight of fuel material selected from the group consisting of parafiin, paraffin-based waxes, and mineral oil with from about 6 parts to about 50 parts by Weight of a acid-resistant surfactant selected from the group consisting of sorbitan monooleate, sor-bitan monopalmitate and sorbitan monostearate and a maximum of about 20 parts by weight of a copolymer methyl vinyl ether-maleic anhydride, mixing from about 300 parts to about 550 parts by weight of nitrate selected from the group consisting of ammonium nitrate and alkali metal nitrates with said blend of fuel material, acid-resistant surfactant and copolymer of methyl vinyl ether-maleic anhydride, adding 100 parts by weight of an aqueous solution of nitric acid containing from about 30% to about 80% by weight of nitric acid, to said blend of fuel material, acid-resistant surfactant, copolymer of methyl vinyl UNITED STATES Patent No. 3,242,019

ether-maleic anhydride and nitrate, agitating said mixture to form an emulsion, heating said emulsion to a temperature less than about 150 F. to form a melt and allowing said emulsion to cool and solidify.

17. A blasting composition in the form of a solid emulsion consisting essentially of 100 parts by weight of an aqueous solution of nitric acid containing from about 30% to about 80% by weight of nitric acid, from about 300 parts to about 550 parts by weight of nitrate selected from the group consisting of ammonium nitrate and alkali metal nitrates, from about 20 parts to about 80 parts by weight of parafiin wax, from about 6 to about parts by weight of sorbitan monopalmitate and a maximum of about 20 parts by weight of a copolymer of methyl vinyl ether-maleic anhydride.

18. A blasting composition in the form of a solid emulsion consisting essentially of 100 parts by weight of an aqueous solution of nitric acid containing from about 30% to about by weight of nitric acid, from about 300 parts to about 550 parts by weight of nitrate selected from the group consisting of ammonium nitrate and alkali metal nitrates, from about 20 parts to about 80 parts by weight of fuel material selected from the group consisting of paraffin wax, parafiin-based Waxes and mineral oil, from about 6 to about 50 parts by weight of an acid-resistant surfactant selected from the group consisting of sorbitan monooleate, sorbitan monopalmitate, and sorbitan monosterate, and a maximum of about 20 parts by weight of a copolymer of methyl vinyl ether-maleic anhydride.

No references cited.

CARL D. QUARFORTH, Primary Examiner. BENJAMIN R. PADGETT, Examiner.

PATENT OF FICE CERTIFICATE OF CORRECTION March 22 1966 Neil E. Gehrig It is hereby certified that error appears in the above numbered patent requiring correction corrected below.

Column 2, 4, line 3, for fourth column,

rence, read ---3.2

and that the said Letters Patent should read as line 18, for "Nntr ic" read Nitric column "slury" read slurry lines 8 and 9 thereof, for "+3 2", each occur column 5, Table I,

- (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,242,019 March 22, 1966 Neil E Gehrig It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 18, for "Nntric" read Nitric column 4, line 3, for "slury" read slurry column 5, Table I, fourth column, lines 8 and 9 thereof, for "+3n2", each occurrence, read 3,2

Singed and sealed this 5th day of September 1967.

(SEAL) Atteet:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Offioer Commissioner of Patents 

1. A BLASTING COMPOSITION IN THE FORM OF A SOLID EMULSION CONSISTING ESSENTIALLY OF 100 PARTS BY WEIGHT OF AN AQUEOUS SOLUTION OF NITRIC ACID CONTAINING FROM ABOUT 30% TO ABOUT 80% BY WEIGHT OF NITRIC ACID, FROM ABOUT 300 TO ABOUT 550 PARTS BY WEIGHT OF AMMONIUM NITRATE, FROM ABOUT 20 TO ABOUT 80 PARTS BY WEIGHT OF AN INSENTIVE, IMMISCIBLE FUEL MATERIAL, AND FROM ABOUT 6 TO ABOUT 50 PARTS BY WEIGHT OF AN ACIDRESISTANT SURFACTANT.
 12. A METHOD OF PREPARING A BLASTING COMPOSITION COMPRISING THE STEPS OF BLENDING FROM ABOUT 20 PARTS TO ABOUT 80 PARTS BY WEIGHT OF INSENSITIVE, IMMISCIBLE CARBONACEOUS FUEL WITH FROM ABOUT 6 PARTS TO ABOUT 50 PARTS BY WEIGHT OF A ACID-RESISTANT SURFACTANT, MIXING FROM ABOUT 300 PARTS TO ABOUT 550 PARTS BY WEIGHT OF NITRATE SELECTED FROM THE GROUP CONSISTING OF AMMONIUM NITRATE AND ALKALI METAL NITRATES WITH SAID BLEND OF CARBONACEOUS FUEL AND ACID-RESISTANT SURFACTANT, ADDING 100 PARTS BY WEIGHT OF AN AQUEOUS SLUTION OF NITRIC ACID CONTAINING FROM ABOUT 30% TO ABOUT 80% BY WEIGHT OF NITRIC ACID TO SAID BLEND OF FUEL, SURFACTANT AND NITRATE, AGITATING SAID MIXTURE TO FORM AN EMULSION, HEATING SAID EMULSION TO A TEMPERATURE LESS THAN ABOUT 150*F. TO FORM A MELT AND ALLOWING SAID EMULSION TO COOL AND SOLIDIFY. 